Pocket-type



March 10, 1964 3,124,440

G. W. HOGG POCKET-TYPE FILTER STRUCTURE Filed April 20. 1961 INVENTOGEORGE W. HO

AT'ILORNEY United States Patent 3,124,440 PUCKEFTYFE FILTER STRUCTUREGeorge W. Hogg, Louisville, Ky, assignor to American Air FilterQornpany, Inca, Louisville, Ky, a corporation of Delaware Filed Apr. 20,1961, Ser. No. 104,357 3 Claims. (Cl. 55484) This invention relates tofluid filters and more particularly to improved high efficiencypocket-type filters for filtering contaminants from a dirty gas stream.

In accordance with the present invention an economic, efiicient and easyto assemble structural arrangement is obtained for pocket gas filters ofa type similar to that disclosed in assignees co-pending applicationSerial No. 104,200, filed April 17, 1961. Further, with the structuralarrangement for pocket-type filters as disclosed herein, it is possibleto provide broad variations in pocket contour without restrictions dueto filter material thickness. Moreover, the structural arrangement ofthe present invention insures firm and uniform application ofpocketformed filter media to a support frame, permitting readyadjustment to posible changes in size between media and support frameand avoiding some of the expensive stamping and casting proceduresheretofore required in the art.

Various other features of the present invention will become obvious toone skilled in the art upon reading the disclosure set forthhereinafter.

More particularly, the present invention provides in a pocket-typefilter structure wherein a pleat of flexible filtering material isdivided into at least two pocket members having an open-end mouthimmediately adjacent supporting portions of the pleat with the pleatbeing fastened through the supporting portions to a frame having a gasinlet passage co-operable with the open-end mouth of the pleat, a pliantskirt means fastened to the supporting portions of the pleat and bent todisplace the supporting portions to form the open-end mouth of thepocket members into individual openings for each pocket member, thepliant skirt means including apron portions fastened to the frame sothat individual openings of the pleat are aligned with the gas inletpassage of the frame.

It is to be understood that various modifications can be made in thearrangement, form and construction of the apparatus disclosed hereinwithout departing from the scope or spirit of the present invention.

Referring to the drawing:

FIGURE 1 is an overall oblique view of a pocket-type filter arrangementof the present invention, including an apertured frame member arrangedto support separate pocket-formed pleats formed from Webs of flexiblefiltering material;

FIGURE 2 is an enlarged oblique view of a portion of a pliant skirtstrip pair which can be fastened to the supporting portions of a pleat,bent and subsequently fastened to an apertured support frame as inFIGURE 1;

FIGURE 3 is an oblique View of the skirt strip portions of FIGURE 2,disclosing one of the strips fastened to a pleat supporting portion Withthe apron portions of the strip bent at right angles to the fasteningportion of the strip;

FIGURE 4 is an exploded oblique view of a pocket member portion andapertured frame portion prior to assembly, disclosing a skirt stripportion after it has been bent to displace the supporting portion of thepleat to which is has been fastened;

FIGURE 5 is a cross-sectional plan view of the downstream side of asupport frame with pocket members assembled thereto.

Referring to FIGURE 1 of the drawings, a plurality of spacedpocket-formed pleats are disclosed as connected to and supported byapertured frame 2. Pleats 3,124,440 Patented Mar. 10, 1964 10advantageously can be similar to the pocket-formed pleats of assigneesaforementioned co-pending application Serial No. 104,200 and, as such,can be made from any one of a number of suitable gas filtering materialswhich are relatively non-stretchable and porous. Advantageously, a wovenfabric or a fibrous glass type material having fibers of substantiallyone micron in size can be used. To provide tensile strength to pleats 10and to insure that the pleats are properly supported when positioned inthe fluid stream to be filtered, each pleat 10 can be faced with ascrim-type material 5, this material being stronger in nature than thepleat and of maximum porosity. As in applicants aforementioned copendingapplication, each pleat is formed from a web of flexible filteringmaterial that is provided with a midpoint fold line 3 which divides eachweb into a pair of pleat forming sections 4 having terminal supportingportions 6 remote from fold line 3. The pleat forming sections arefolded to face each other and form the pleat 10. Spaced seams 7 are thenextended across the pleat transverse fold line 3 to join the facingsections of the pleat and form a plurality of pocket members having anopen-end mouth immediately adjacent the supporting portions 6 of thepleat. Seams 7 can be stitched or, if desired and like the seams in theaforementioned application, can be comprised of a plurality of spacedstaples 8 with reinforcing member coupled therewith to minimize tearing.Since construction of the pleats 10 with the rows of side-by-sidepockets is fully disclosed in assignees aforementioned co-pendingapplication, further details thereof are not set forth herein.

As can be seen in the drawings and in accordance with the invention, tosupport pleats 10 in a fluid stream to be treated, apertured frame 2 isdisclosed. This apertured frame includes spaced parallel rows 9 of gasinlet passages in the form of spaced apertures 11. Although apertures 11are disclosed as hexagonal in shape, it is to be understood that othershapes can be used if so desired.

Referring to FIGURES 2-5 inclusive, the novel structural arrangement forfastening pocket-formed pleats 10 to apertured frame 2 is disclosed.This arrangement includes pairs of opposed skirt strips 12 of pliantmaterial, the strips of each pair being mirror images of each other witheach of strips 12 including a fastening portion 13 and apron portions14- (FIGURE 2). It is to be understood that strips 12 can be formed fromany one of a number of well known pliant materials and, advantageously,can be stamped from thin gauge aluminum sheet. In this connection, it isto be noted that in stamping skirt strips 12, apron portions 14 of thepairs of strips are made of suitable shape to conform with theperipheral contour of apertures 11 in frame 8 after strips 12 have beenbent and are ready to be assembled to frame 8 (as describedhereinafter). Once strips 12 of a pair have been stamped out, thefastening portions 13 of the strips can be coated with a suitableadhesive, such as a neoprene cement, and the strips can then be broughtinto facing engagement with the outside walls of supporting portions 6of a pocket-formed pleat 10. At this point, apron portions 14 of thestrips can be turned at right angles to the fastening portions 13 of thestrips. It is to be understood that, if desired, the turning of apronportions 14 also can be accomplished prior to actual fastening of thestrips to the supporting portion of a pleat. It further is to beunderstood that apron portions of one strip of a pair extends at rightangles from the fastening portion of such strip in a direction oppositeto the direction in which the apron portions of the other strip of thepair extends. Once a pliant pair of strips has been appropriatelyassembled to supporting portions 6 of a pleat 10, the strips of the paircan be manually bent in an opposing manner to conform with the aperturesof the frame with which they are to be assembled. In this connection, itis to be noted that the bending of strips 12 causes fastening portions13 of the strips to displace the supporting portions of the pleat insuccessively opposed crests and valleys to form individual openingssubstantially aligned with the pocket members of the pleat.

Referring to FIGURE 4 of the drawings, when this has been accomplished,pleat It) is assembled to the apertured frame with the individualopenings of the pleat, which openings are substantially in alignmentwith the pocket members of the pleat, also in alignment with the spacedapertures 11 of an apertured row 9 in frame 8. It is to be understoodthat any suitable means for fastening apron portions 14 of strips 12 tothe downstream side of frame 8 can be used; for example, the bonding ofthe apron portions to the frame can be accomplished by stapling, spotwelding, by use of an adhesive or by riveting. It also is to beunderstood that, if desired, the apron portions of the strips caninclude tab members which can be adopted to engage in slots providedaround the periphery of the apertures of frame 8 (not shown), the tabmembers subsequently being folded over to thus provide a quick connectand disconnect arrangement for the pleat and frame. Finally, it is to benoted that the simple and efiicient pliant skirt strip construction Withthe subsequent forming of apertures in the supported pleat, not onlyprovides an efiicient and novel arrangement for assembling flexiblefiltering pocket-type material to a support frame, but, in addition, thepliant skirt strips serve as strengthening ribs to give torsional anddimensional stability to the frame with which they are associated.

The invention claimed is:

1. A pocket type fluid filter comprising:

(a) spaced pleats of flexible filtering material with each pleat dividedinto at least two pocket members having an open-end mouth immediatelyadjacent 0pposite supporting portions of said pleat;

(19) frame means including a plurality of spaced parallel rows of spacedapertures;

(c) a plurality of pairs of separate contiguous skirt strips of pliantmateral;

(d) each of said skirt strip pairs being fastened to said oppositesupporting portions of a pleat and bent 4 one with respect to the otherin mirror image form to displace said supporting portions incontinuously running successively opposed crests and valleys to formapertures substantially in alignment With said pocket members of saidpleat and in conformation in shape to the apertures of said frame; and,

(e) apron means to fasten said skirt strip pairs to said frame to extendalong the periphery of the aperture roWs in said frame so that theapertures formed by each of said skirt strip pairs in a pleat aresubstantially aligned with the spaced apertures of an aperture row ofsaid frame.

2. A pocket type fluid filter comprising:

(a) a pleat of flexible filtering material divided into at least twopocket members having an open-end mouth immediately adjacent oppositesupporting portions of said pleat;

(b) frame means including a row of spaced apertures;

(c) continuous skirt strip means of pliant material;

(d) said skirt strip means being fastened to said opposite supportingportions of said pleat and bent along said opposite supporting portionsin mirror image form so as to displace said supporting portions incontinuous running successively opposed crests and valleys to formapertures substantially in alignment with said pocket members of saidpleat and in conformation in shape to the apertures of said frame; and,

(e) apron means to fasten said skirt strip means to said frame to extendalong the periphery of the aperture rows in said frame so that theapertures formed in said pleat by said skirt strip means aresubstantially aligned with the apertures of said frame.

3. The apparatus of claim 2, said apron means comprising tab membersintegral with said strip means and extending substantially at rightangles away from said apertures formed by said strip means to face saidframe means for assembly thereto.

References Cited in the file of this patent UNITED STATES PATENTS

1. A POCKET TYPE FLUID FILTER COMPRISING: (A) SPACED PLEATS OF FLEXIBLEFILTERING MATERIAL WITH EACH PLEAT DIVIDED INTO AT LEAST TWO POCKETMEMBERS HAVING AN OPEN-END MOUTH IMMEDIATELY ADJACENT OPPOSITESUPPORTING PORTIONS OF SAID PLEAT; (B) FRAME MEANS INCLUDING A PLURALITYOF SPACED PARALLEL ROWS OF SPACED APERTURES; (C) A PLURALITY OF PAIRS OFSEPARATE CONTIGUOUS SKIRT STRIPS OF PLIANT MATERIAL; (D) EACH OF SAIDSKIRT STRIP PAIRS BEING FASTENED TO SAID OPPOSITE SUPPORTING PORTIONS OFA PLEAT AND BEND ONE WITH RESEPECT TO THE OTHER IN MIRROR IMAGE FORM TODISPLACE SAID SUPPORTING PORTIONS IN CONTINUOUSLY RUNNING SUCCESSIVELYOPPOSED CRESTS AND VALLEYS TO FORM APERTURES SUBSTANTIALLY IN ALIGNMENTWITH SAID POCKET MEMBERS OF SAID PLEAT AND IN CONFORMATION IN SHAPE TOTHE APERTURES OF SAID FRAME; AND, (E) APRON MEANS TO FASTEN SAID SKIRTSTRIP PAIRS TO SAID FRAME TO EXTEND ALONG THE PERIPHERY OF THE APERATUREROWS IN SAID FURNACE SO THAT THE APERTURES FORMED BY EACH OF SAID SKIRTSTRIP PAIRS IN A PLEAT ARE SUBSTANTIALLY ALIGNED WITH THE SPACEDAPERTURES OF AN APERTURE ROW OF SAID FRAME.